Electric signaling apparatus



2 Sheets-Sheet l I. H. PARNHAM.

ELBGTRIC SIGNALING APPARATUS.

(No Model.)

Patented Oct. 20,

Uz/en-U?? Q @Maw (N'o Model.) 2 sheets-sheen 2 I. H. PARNHAM.

ELECTRIC SIGNALING APPARATUS.

No. 328,578. Patented Oct. 20, 1885.

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IINrrEn STATES PATENT EErcE.

ISAIAH H. FARNHAM, OF DEERING, MAINE, ASSIGNOR TO THE AMERICAN BELLTELEPHONE COMPANY, OF BOSTON, MASSACHUSETTS.

ELECTRIC SIGNALING APPARATUS.

SPECIFICATION forming part of Letters Patent No. 328,578, dated October20, 1835.

Application led August 16, 1884.

To aZZ whom it may concern,.-

Be it known that I, Isararr H. FARNHAM, a citizen of the United States,residing at Deering, in the county of Cumberland and State of Maine,have invented certain Improvements in Electric Signaling Apparatus, ofwhich the following is a specification.

lWIy present invention relates to an improved method of and apparatusfor signaling upon telephone and telegraph lines or other electriccircuits,in cases where it is necessary to place a number of stationsupon the same line or circuit. Since the commercial introduction of thespeaking-telephone, and prior to my invention, many devices have beeninvented to accomplish this end, some of which have proved etticient.Nearly all,however,involve the use of special apparatus which is more orless expensive and complicated.

The object of my invention is to enable the operator at the central orprincipal station of such a line as I have mentioned to sound a call oralarm at any particular station re quired without putting in operationany of the other alarms upon the line, and to effect this result withapparatus of the most ordinary and cheaplyconstructed character at theway-stations, and with no other apparatus at the central station thanwould otherwise be employed.

I have found by practical experience that a series of ve stations upon asingle circuit is as large a number as can profitably be operated, andthat there is little or no demand for a larger number, and I havedevised my method to provide for that number. The method I adopt is tooperate one call of the series by intermittent pulsations ofelectricity. of definite direction-say positive-a second by intermittentpulsations of negative direction, a third by successive pulsations ofrapidly-alternating direction or character, a fourth by a constant andsteady current of positive direction, and the ifth by a constant andsteady current of negative direction.

To this end my invention further consists of mechanism andelectrical-circuit arrangement whereby different modes of operating thesame signal-transmitting apparatus at the central station are enabled toeffectuate results differ ing in character at the sub-stations.

In the accompanying drawings, Figure l is Serial No. 140,722. (Nomodel.)

a perspective view of the station apparatus at two of the stations.Fig.2 is a front View showing adetail thereof and indicating therelative position of some of the working parts. Fig. 3 is a plan of thesame detail,looking down. Fig. 4 is a diagram of the electrical circuitwith the signal transmitting and receiving instruments. Fig. 5 is adetail showing the weight with which I regulate the needle-circuitcloser, and Fig. 6 is a diagrammatic drawing of a modification of theelectrical connections at the central station.

In Letters Patent issued to me February 26,

1884, No. 294,212, is described an annunciator comprising a pivotedmagnetic needle supported vertically between the two cores of anelectro-magnet and adapted to deflect in either directiomaccording tothe direction of an electric current passing through the coils of saidelectro-magnet. In Letters Patent issued to Geo. L. Anders and Theo'. N.Vail, May 31,1881, No. 242,408, a system of signaling is shown whereincontinuous currents of electricity varying not only in direction,butalso in strength, are used in combination with constantly-alternatingpulsations. Suitable instruments adapted to respond to these differingcurrents are also therein described and claimed. Moreover, in LettersPatent issued to Geo. L. Anders, March 22, 1881, N o. 239,134, anarrangement of two signaling-instruments is described, comprising twopolarized bells the armatures of which are each biased normally inopposite directions, so that one of the said bells responds tointermittent pulsations of electricity of positive directionwhile theother responds to like pulsations of negative direction.

My present invention is based upon the subject-matter of my formerpatent, hereinbefore cited, combined with a portion of the inventiondescribed in the patent of Anders and Vail, and with the subject-matterof the patent of Anders, both previously referred to herein, and itconstitutes an improvement and extension of all of the saidpatents,which are here cited as representing the state of the art priorto my invention.

My invention Will be readily comprehended by an examination of thediagram shown at Fig. 4 of the drawings, where there is shown acentral-station apparatus consisting of a IOO battery, amagnetogenerator, a switch, and a system of reversing-keys connectedwith a main line and a series of iive sub-stations, numberedconsecutively from one to live. The signal apparatus at station No. 1gives the signal in consequence of the deflection of a pivotedmagnctized needle normally poised in a vertical plane to a given angle,where it -is adapted to close a local circuit,and thus to ring a bellincluded in such circuit. The appara; tus at station No. 2 gives thesignal in a similar manner, but is adapted toclose its local by adeflection of the needle in a direction opposite to that of No. .1.Stations Nos. 3 and 4 are provided with ordinary polarized bells fittedwith centrally-pivoted armatures biased oppositely with respectto oneanother by springs, so that where No. 3 will ring when a series ofsuccessive positive pulsations are sent, while No. 4 will remain inert,No. 4will respond to a similar succession of negative pulsations, No. 3remaining quiescent.y The bell at station ,5 is, as shown, a polarizedbell of ordinary construction, and is adapted to respond to currents ofrapidly-alternating direction. Being Well known, this instrumentrequires no further description.

I will now describe more particularlyI the instruments at stations No. 1to No. 4.

The bell at No. 4 consists, as shown, of an electro-magnet, M, andcentrally pivoted armature B therefor, both polarized by a horseshoepermanent magnet, N. The said armature is fitted with a bell-hammer, E,adapted to vibrate the gongs D. So 'far the description corresponds tothe bell of No. 5. rIo prevent the bells 4 and 3 from responding tocurrents of thesame class that actuate N o. 5, andfalso'to individualizethem with respect to one another, I attach a flatspring, 82, toastandard, sa, affixed to the frame of the bell, the free end of saidspring being arranged to bear upon one end of the armature R. Thesprings s? of the two bells are fixed to press upon the opposite ends ofthe two armatures, as shown, and thearmature of the bell N o. 4 is thusbiased to hold the bell-hammer normally against the right-hand gong,while the armature of No. 4holds its bell-hammer normally biased againstthe left-hand gong. The.

- armature of N o. 3 is thus actuated to ring by currents of givendirection, While that'of No. 4 is actuated by currents of oppositedirection, as fully shown and4 described in the patent of Anders,hereinbeforeV cited. Being thus oppositely biased with respect to oneanother, it is clear that rapidly-alternating currentsf such as thoseadapted to ring No. 5,-will not cause them to vrespond,since thetransitions in such alternations are too quick for biased arma-f turesto follow. v On the other hand, the bell No. 5 canfnever make butasinglestrokewhen either of the two bells, No. 3 or No. 4, are rung, because itis only energized by currents of successivelyalternate' direction. l

Referring now to the instruments Nos. 1 and 2, which are also separatelyshown in Figs. 2 and 3, they consist of an electro-magnet, M', includedby wires m and n in the linecircuit, and lixed horizontally behind thedial B, so that its cores approach close to the inner side of said dial.The cores of the magnet are attached to a yoke or back piece, u, of sucha length as to bring the cores of the magnetspools a distance apartapproximately equal to the length of a permanently-magnetizedbar orneedle, i, which is pivoted at Z in the center of the dial, and which ismade heavier at one end, so that it will hang vertically between themagnet-cores, although in front thereof. The weight of this lower endmay be made adjustable by the attachment of the sliding sleeve k,made ofany suitable metal, and adapted to fit firmly upon the end of themagnetized bar, while it is capable of being slid to any positionthereon. It may be made to clasp the bar orV needle by means of thefrictionspring s.

A vibrating electro-magnet bell, c, is provided and is connected withone pole of the local battery L B, which, if preferred, may be used alsoto energize the transmitting-telephone. f The other pole of the batteryis connected by Wire p with the magnetized needle or its aXis, andanother wire is run from the remaining binding-screw of the bell to afixed contact-arm, j, which by a screw, o, is attached to the dial; or,if preferred, it may be fixed to the frame in the rear of the dial, andin that case the contact-,point of the arm is caused to protrude throughdiall and to stand in position to engage the pivoted needle whendeflected. The contact-arms of the instrument at No. 1 and at No. 2 are`placed upon opposite sides ofthe needle, and thus contact is made andthe local'circuit closed through the bell C, in one case, with a steadyand nonintermitting positive current i and in the other with a steadynon-intermitting negative current. When the local circuits of either areclosed, the corresponding bell rings. I have found by practicalexperience that these needles will not deflect, except to aninconsiderable amount in either direction when the intermittent currentsadapted to actuate the bells Nos.V 3 and 4, or when the rapidalternations necessary to ring 5 are passing through' l the line, andthat, per contra., when the steady current required to deflectthe'needle is sent,V no effect, except occasionally a light singlestroke is manifested at the other three instruments in circuit. In theperspective View,' Fig. 1, I have shown this arrangement combined in atelephonie outt with a magnetoelectric generator operated by theforcible detachment from a pair of electro-magnets in` eluded in theline-circuit and attached to the poles of apermanent magnet, the Wholebeing inclosed in a case, A. B is the pivoted needle, and A thepush-button, whichV detaches rIhe transmitting-telephone 'I" IOO IIO

needle and its connections equally well to the ordinary crank-operatedmagneto-generator, and in many cases this form would be preferred.

Returning to Fig. 4, I have shown the main line L as terminating in abutton-switch, S, which may be turned on either of the two buttons a andb. When turned onto the button a, the line is continued to groundthrough the magneto-machine M and the wires f and e. The bell No. 5 maynow be rung by the said machine, the four other bells remaininginresponsive. When the switch is turned onto the button b, the line isnormally continued to the ground via button b, wire g', key la, backcontact-bar, c, key k, and ground-wire h. Vhen key k is tappedsuccessively a number of times a corresponding series of negativecurrents are transmitted to line by the following route: ground-wire h,key k', back contactbar, c, battery M B, anvil-contact d, key k, wire g,and button b, to line, ringing one of the two bells 3 or 4-say 4.Tapping in a similar way upon key k has theeffect of reversing thebattery, and will ring bell 3. A steady pressure upon either key willsend a continuous and unbroken current to line of direction dependingupon the key pressed. lThis current will in either case deflect bothneedles of instruments l and 2, but in one case will bring the needle ofNo. l into contact with the contact-point, deflecting the needle of No.2 farther away from its point, and in the other case the opposite resultwill be achieved. The whole ve bells may thus be individually operated.

Although I have shown but one line, and so far have but indirectlyindicated that my invention may be efficiently utilized in combinationwith a telephone-exchange, it is evident that any number of lines may beworked equally well from the same central-station apparatus. I haveaccordingly shown in Fig. 6 an arrangement of the central-stationinstrumentalities which I have found very effectual in actual use.

L represents a subscribers line, and 1,2, 3, 4, and 5, the severalstations located thereon. The line terminates at the distant end, asusual, at the earth, while at the central-station end it is led througha spring-jack, J, and by the wire L2 to the annunciator r and then toground. Any number of lines may be so connected and arranged in aswitch-board common to the series in a manner well understood.

W is a wedge adapted for insertion into the spring-jack, and controllingan instrumentloop, which, when the wedge is thrust into the spring-jack,becomes Virtually a part of the line. The wedge W consists of a block ofinsulating material, 102, carrying on its upper side a metalspring-plate, w, provided at the spring end with a press-knob, la.

Immediately under the press-knob a contact-point, d, is afiixed to theinsulatingblock, and when the knob is pressed a contact-point on itslower surface is brought into connection with the point d. Normally,however, the spring w presses upward against the back limit, z, thisbeing also an electrical contact leading to the office-telephones T andT by the wires 11 and 12, and thence by wire 13 to the plate w', whichis iiXed to the lower side of the wedge. When the wedge is thrust intothe spring-jack and the knob k left unpressed, the effect is simply tointroduce the telephones into the line-circuit. A buttonswitch, S, isprovided which has three positions, as shown. One of the buttons onwhich it may be placed may be marked p, and is connected with thepositive pole of a callingbattery whose negative pole is to earth. Asecond button is marked N, and is connected with the negative pole of asecond battery equal to the first, but with positive pole to earth. Thethird button is connected with a magnetogenerator. The switchlever S isunited by a wire, 10, with the contact-anvil. When, now, the wedge W isinserted in any spring-jack and the switch S is placed on the button P,the key k may be pressed steadily on the anvil d, to send a steady andcontinuous positive current to line, or it may be tapped repeatedly tosend intermittent currents to line. Vhen the switch is placed on thebutton N, the same operations will send continuous and intermittentnegative currents to line; and, finally,when the switch is placed on thethird button and the key steadily pressed, magneto-electric currentswhich are of alternate direction are sent to line. The magneto-generatormay of course be driven either by power or hand, as may be foundconvenient.

Wherever in this specification I have referred to a generator as aninstrument for sending currents of rapidly-alternating direction, itmust be understood that I may, without prejudice to my invention, use abattery and pole-changer.

I claim- The combination,with a subscribers line of a telephone-exchangesystem, said line comprising five signaling-instruments, each located ata different sub station, and each adapted to give an individual signal,of a springjack forming a part of said line, and a looping-wedge adaptedfor insertion in said spring-jack, together with a single key affixed tosaid wedge, a button-switch connected with the contact-anvil of saidkey, a series of contact-buttons for said switch, separate batteries IOOIIO

with opposite poles to ground connected with two of the said buttons,and a generator or currentreverser connected with the other button,substantiallyas set forth.

In testimony whereof'Ihave signed my name to this specification, in thepresence of two subscribing witnesses, this 1st day of August, A. D.1884.

Witnesses:

A. W. CooMBs, C. H. TOLMAN.

ISAIAH H. FARNIIAM.

